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PSI AP ChemistryEquilibrium Multiple ChoiceName_________________________Part A: Introduction to Equilibrium and ICE TablesAt equilibrium, __________. all chemical reactions have ceased the rates of the forward and reverse reactions are equal the rate constants of the forward and reverse reactions are equal the value of the equilibrium constant is 1 the limiting reagent has been consumed Use the following information to answer questions 2-3A(g) ? 2C(g) + D(s)39052514160500At what time does the reaction below reach equilibrium?Around 2 minutesAround 3 minutesAround 5 minutesAround 8 minutesAround 10 minutesWhat would be the value of the equilibrium constant for the reaction above?1.23.60.8331.83.0Which of the following compounds is the least soluble? Compound Ksp_______ MnCO3 1.8 x 10-11 CuS 6.3 x 10-36 CdS 8.0 x 10-27 PbS 8.0 x 10-28 MnCO3 CuS CdSPbSboth CdS and PbSWhich of the following expressions is the correct equilibrium-constant expression for the equilibrium between dinitrogen tetroxide and nitrogen dioxide?N2O4(g) ? 2NO2(g)[NO2]/[ N2O4] [NO2]2/[ N2O4] [NO2]/[ N2O4]2[NO2] [ N2O4] [NO2]2 [ N2O4] Which of the following expressions is the correct equilibrium-constant expression for the reaction below? (NH4)2Se(s) ? 2NH3(g) + H2Se(g)[NH3][ H2Se]/(NH4)2Se(NH4)2Se/[NH3]2[ H2Se] 1/[(NH4)2Se ] [NH3]2[ H2Se] [NH3]2[ H2Se]/ [(NH4)2Se ] Which of the following expressions is the correct equilibrium-constant expression for the reaction below? HF(aq) + H2O(l) ? H3O+(aq) + F-(aq)[HF][H2O]/ [H3O+][F-] 1/HF[H3O+][F-]/[HF][H2O] [H3O+][F-]/[HF][F-]/[HF] The equilibrium-constant expression for the reaction below is____________.Ti(s) + 2Cl2(g) ? TiCl4(l)[TiCl4]/[Ti][ Cl2] [Ti][ Cl2]2/ [TiCl4] [TiCl4]/[ Cl2]2[ Cl2]-2[TiCl4]/[Ti][ Cl2]2The equilibrium constant for the gas phase reaction N2(g) + 3H2(g) ?2NH3(g) is Keq = 4.34x10-3 at 300 °C. At equilibrium, __________. products predominate reactants predominate roughly equal amounts of products and reactants are present only products are present only reactants are present The equilibrium constant for the gas phase reaction 2NH3(g) ? N2(g) + 3H2(g) is Keq = 230 at 300 °C. At equilibrium, __________. products predominate reactants predominate roughly equal amounts of products and reactants are present only products are present only reactants are present The reaction A(g) ?B(g) has a K value of 4.1 x 102. At equilibrium, which of the following would be true?[A] = [B][A] > [B][A] < [B]The following reactions have equilibrium values all measured at 500 K. Arrange them in order of increasing tendency to proceed to completion (least completion greatest completion).1) 2NOCl ? 2NO + Cl2Kp = 1.7 x 10-22) N2O4 ? 2NO2Kp = 1.5 x 1033) 2SO3 ? 2SO2 + O2Kp = 1.3 x 10-54) 2NO2 ? 2NO + O2Kp = 5.9 x 10-52 < 1 < 3 < 44 < 3 < 1 < 23 < 1 < 4 < 23 < 4 < 1 < 24 < 3 < 2 < 1Consider the following equilibrium: 2SO2(g) + O2(g) ? 2SO3(g) The equilibrium cannot be established when __________ is/are placed in a 1.0-L container. 0.25 mol SO2(g) and 0.25 mol O2(g) 0.75 mol SO2(g) 0.25 mol SO2(g) and 0.25 mol SO3(g)0.50 mol O2(g) and 0.50 mol SO3(g)1.0 mol SO3(g)Consider the following chemical reaction: H2(g) + I2(g) ? 2HI(g). At equilibrium in a particular experiment, the concentrations of H2, I2, and HI were 0.25M, 0.043M, and 0.65M respectively. The value of Keq for this reaction is __________. 60.46 111 9.0x10-33.93 39.30 The equilibrium constant (Kp) at 721 K for the reaction 2HI(g) ? H2(g) + I2(g) is 0.0198. In a particular experiment, the partial pressures of H2 and I2 at equilibrium are 0.710 and 0.888 atm, respectively. The partial pressure of HI is __________ atm. 7.87 1.98 5.64 0.125 0.389 A reaction vessel is charged with hydrogen iodide, which partially decomposes to molecular hydrogen and iodine: 2HI(g) ? H2(g) + I2(g). When the system comes to equilibrium at 425 °C, PHI = 0.808atm, and P(H2) = P(I2) = 0.0860atm. The value of Kp at this temperature is __________. 9.15x10-3 1.30 x10-2Kp cannot be calculated for this gas reaction when the volume of the reaction vessel is not given. 54.3 1.13 x10-2At high temperatures, molecular hydrogen and molecular bromine react to partially form hydrogen bromide: H2(g) + Br2(g) ? 2HBr(g) A mixture of 0.682 mol of H2 and 0.440 mol of Br2 is combined in a reaction vessel with a volume of 2.00 L. At equilibrium at 700 K, there are 0.566 mol of H2 present. At equilibrium, there are __________ mol of Br2 present in the reaction vessel. 0.200 0.480 0.500 0.400 0.324Dinitrogentetraoxide partially decomposes according to the following equilibrium: N2O4(g) ? 2NO2(g). A 1.00-L flask is charged with 0.055mol of N2O4. At equilibrium at 373 K, 0.0065 mol of N2O4 remains. Keq for this reaction is __________. 2.2 x10-40.097 0.22 0.0485 1.45 Carbon monoxide is converted to carbon dioxide via the following reaction: CO(g) + H2O(g) ? CO2(g) + H2(g) In an experiment, 0.45 mol of CO and 0.30 mol of H2O were placed in a 1.00-L reaction vessel. At equilibrium, there were 0.19 mol of CO remaining. Keq at the temperature of the experiment is __________. 4.47 0.55 8.890.63 1.0 A sealed 1.0 L flask is charged with 0.600 mol of I2 and 0.600 mol of Br2.I2(g) + Br2(g) ? 2IBr(g) When the contents achieve equilibrium, the flask contains 0.80 mol of IBr. The value of Keq is ______. 6.4 4.0 167.1 3.5 Nitrosyl bromide decomposes according to the following equation.2NOBr(g) ? 2NO(g) + Br2(g).A sample of NOBr (0.64 mol) was placed in a 1.00-L flask containing no NO or Br2. At equilibrium the flask contained 0.46 mol of NOBr. How many moles of NO and Br2, respectively, are in the flask at equilibrium? 0.18, 0.18 0.46, 0.23 0.18, 0.090 0.18, 0.360 0.46, 0.46 Two moles of gas A are placed in a one liter vessel and decompose into the gaseous products B and C according to the equation 2A(g) ? B(g) + C(g). If it is 40.0% dissociated at equilibrium, what is the value of the equilibrium constant?.025.011.012.111At 22 °C, Kp = 0.070 for the equilibrium: NH4HS(s) ? NH3(g) + H2S(g)A sample of solid NH4HS is placed in a closed vessel and allowed to equilibrate. Calculate the equilibrium partial pressure (atm) of ammonia, assuming that some solid NH4HS remains. 0.26 0.070 0.52 4.9 x10-33.8 At 100°C the reaction below has an equilibrium constant, Keq, value of 2.2x10-10. If 1.00 mol of phosgene, COCl2, is placed in a 10.0 L flask, calculate the concentration of carbon monoxide at equilibrium. COCl2(g) ? CO(g) + Cl2(g)0.075 4.7x10-50.52 4.7x10-60.154The equilibrium constant (Kp) for the interconversion of PCl5 and PCl3 is 0.0121: PCl5(g) ? PCl3(g) + Cl2(g) . A vessel is charged with PCl5, giving an initial pressure of 0.123 atm. At equilibrium, the partial pressure of PCl3 is __________ atm. 0.0782 0.0455 0.0908 0.0330 0.123 At 200 °C, the equilibrium constant (Kp) for the reaction below is. 2NO(g) ? N2(g) + O2(g)A closed vessel is charged with 36.1 atm of NO. At equilibrium, the partial pressure of O2 is _________ atm. 294 35.7 17.9 6.00 1.50x10-2For which one of the following is the value of Kp smaller than that of Kc at 25?C?H2(g) + F2(g) ? 2HF(g)2SO3(g) ? 2SO2(g) + O2(g)Al2(SO3)3(s) + 6HCl(g) ? 2AlCl3(s) + 3H2O(l) + 3SO2(g)NH4Br(s) + KOH(s) ? NH3(g) + KBr(s) + H2O(l)2HF(g) ? H2(g) + F2(g)For which one of the following does Kc = Kp at 25?C?H2(g) + F2(g) ) ? 2HF(g)2SO3(g) ? 2SO2(g) + O2(g)Al2(SO3)3(s) + 6HCl(g) ? 2AlCl3(s) + 3H2O(l) + 3SO2(g)NH4Br(s) + KOH(s) ? NH3(g) + KBr(s) + H2O(l)N2(g) + 3 H2(g) 2 NH3(g)Given the following reaction at equilibrium, if Kc = 6.44x105 at 230.0 °C, Kp = __________. 2NO(g) + O2(g) ? 2NO2(g)3.67 x10-21.56 x1046.44 x1052.66 x1062.67 x107Given the following reaction at equilibrium, if Kp =1.05 at 250.0 °C, Kc = __________. PCl5(g) ? PCl3(g) + Cl2(g)3.90x10-6 2.45x10-21.05 42.9 45.0 Part B: Le Chatelier’s Principle, Q, and Calculating K ValuesAt 400 K, the equilibrium constant for the reaction Br2(g) + Cl2(g) ? 2BrCl(g) is Kp = 7.0. A closed vessel at 400 K is charged with 1.00 atm of Br2, 1.00 atm of Cl2, and 2.00 atm of BrCl. Use Q to determine which of the statements below is true. The equilibrium partial pressures of Br2, Cl2 , and BrCl will be the same as the initial values. The equilibrium partial pressure of Br2 will be greater than 1.00 atm. At equilibrium, the total pressure in the vessel will be less than the initial total pressure. The equilibrium partial pressure of BrCl will be greater than 2.00 atm. The reaction will go to completion since there are equal amounts of Br2 and Cl2. For the reaction, 2SO2(g) + O2(g)2SO3(g), at 450.0 K the equilibrium constant, Kc, has a value of 4.62. A system was charged to give these initial concentrations, [SO3] = 0.254 M, [O2] = 0.00855 M, [SO2] = 0.500 M. In which direction will it go?to the right or the left depending on the pressure to the left it will remain at the same concentrations to the right to the right or the left depending on the volumeWhich of the following statements is true? Q does not change with temperature. Keq does not change with temperature, whereas Q is temperature dependent. K does not depend on the concentrations or partial pressures of reaction components. Q does not depend on the concentrations or partial pressures of reaction components. Q is the same as Keq when a reaction is at equilibrium. How is the reaction quotient used to determine whether a system is at equilibrium? The reaction quotient must be satisfied for equilibrium to be achieved. At equilibrium, the reaction quotient is undefined. The reaction is at equilibrium when Q < Keq. The reaction is at equilibrium when Q > Keq. The reaction is at equilibrium when Q = Keq. Consider the following reaction at equilibrium:2NH3(g) ? N2(g) + 3H2(g)ΔH° = +92.4 kJLe Chatelier's principle predicts that adding N2 to the system at equilibrium will result in _________. a decrease in the concentration of NH3a decrease in the concentration of H2an increase in the value of the equilibrium constant a lower partial pressure of N2removal of all of the H2Consider the following reaction at equilibrium: 2CO2(g) ? 2CO(g) + O2(g)ΔH° = -514 kJ Le Chatelier's principle predicts that adding O2 (g) to the reaction container will____. increase the partial pressure of CO at equilibrium decrease the partial pressure of CO2 at equilibrium increase the value of the equilibrium constant increase the partial pressure of CO2 at equilibrium decrease the value of the equilibrium constant Consider the following reaction at equilibrium: 2CO2(g) ? 2CO(g) + O2(g)ΔH° = -514 kJ Le Chatelier's principle predicts that an increase in temperature will __________. increase the partial pressure of O2decrease the partial pressure of CO2decrease the value of the equilibrium constant increase the value of the equilibrium constant increase the partial pressure of CO Consider the following reaction at equilibrium: 2SO2(g) + O2(g) ? 2SO3(g)ΔH° = -99 kJ Le Chatelier's principle predicts that an increase in temperature will result in _______. a decrease in the partial pressure of SO3a decrease in the partial pressure of SO2an increase in Keqno changes in equilibrium partial pressures the partial pressure of O2 will decrease Of the following equilibria, only __________ will shift to the left in response to a decrease in volume. H2(g) + Cl2(g) ? 2HCl(g) 2SO3(g) + 2SO2(g) + O2(g)N2(g) + 3H2(g) ? 2NH3(g) 4Fe(s) + 3O2(g) ? 2Fe2O3(s) 2HI(g) ? H2(g) + I2(g) In which of the following reactions would increasing pressure at constant temperature not change the concentrations of reactants and products, based on Le Chatelier's principle? N2(g) + 3H2(g) ? 2NH3(g)N2O4(g) ? 2NO2(g) N2(g) + 2O2(g) ? 2NO2(g) 2N2(g) + O2(g) ? 2N2O(g) N2(g) + O2(g) ? 2NO(g)The reaction below is exothermic: 2SO2(g) + O2(g) ? 2SO3(g)Le Chatelier's Principle predicts that __________ will result in an increase in the number of moles of SO3 in the reaction container. increasing the pressure decreasing the pressure increasing the temperature removing some oxygen increasing the volume of the container For the endothermic reaction CaCO3(s) ? CaO(s) + CO2(g), Le Chatelier's principle predicts that __________ will result in an increase in the number of moles of CO2. increasing the temperature decreasing the temperature increasing the pressure removing some of the CaCO3none of the above The effect of a catalyst on equilibrium is to __________. increase the rate of the forward reaction only increase the equilibrium constant so that products are favored slow the reverse reaction only increase the rate at which equilibrium is achieved without changing the composition of the equilibrium mixture shift the equilibrium to the right Consider the following system, which is at equilibrium, 3C(s) + 3H2(g)CH4(g) + C2H2(g) The result of removing some C(s) from the system will be: Kc increases more C(s) is produced no further change occurs more CH4(g) and C2H2(g) are produced to restore the equilibriummore C2H2(g) is consumed to restore the equilibrium For questions 45-48, consider the following equilibrium system.I2(g) + Cl2(g) ? 2 ICl (g) + heat (A) (B)(C) (D)The graphs above represent concentration vs reaction progress. Identify the graph that best represents each of the following stresses and shift.________adding I2(g) ________removing Cl2(g) ________increasing the temperature ________increasing the volume Consider the following equilibrium reaction:N2O4(g) 2NO2(g)4318005905500At time t1, heat is applied to the system. Which of the following best describes theequilibrium reaction and the change in Keq?exothermic and Keq increasesexothermic and Keq decreasesendothermic and Keq increasesendothermic and Keq decreasesConsider the following equilibrium: CH3COOH(aq) ? CH3COO-(aq) + H+(aq) + heatA stress was applied at time t1 and the data plotted on the following graph:The stress imposed at time t1 is the result of?323850012700time t1[H+]00time t1[H+]??the addition of HCldecreasing the temperaturethe addition of NaCH3COOincreasing the volume of the container?The Keq for the equilibrium below is 0.135 at 700.0 ° C.SO2(g) + ?O2(g) ? SO3(g).What is the value of Keq at this temperature for the following reaction? SO3(g) ? SO2(g) + ?O2(g)0.224 0.0185 0.112 7.40 -0.112 The value of Keq for the equilibrium H2(g) + I2(g) ? 2HI(g) is 890 at 25 °C. What is the value of Keq for the equilibrium below??H2(g) + ?I2(g) ? HI(g) 397 0.035 29.83 1588 0.0013 The value of Keq for the following reaction is 0.20:SO2(g) + NO2(g) ? SO3(g) + NO(g).The value of Keq at the same temperature for the reaction below is _______. 2SO2(g) + 2NO2(g) ? 2SO3(g) + 2NO(g) 0.50 0.04 0.12 0.25 16 The value of Keq for the equilibrium H2(g) + I2(g) ? 2HI(g) is 54.0 at 427 °C. What is the value of Keq for the equilibrium below?HI(g) ? ?H2(g) + ?I2(g)27 7.35 0.136 2.92x103 3.43x10-4The Keq for the equilibrium below is 6.5x10-2 at 480.0 °C. 2Cl2(g) + 2H2O(g) ? 4HCl(g) + O2(g)What is the value of Keq at this temperature for the following reaction?2HCl(g) + ?O2(g) ? Cl2(g) + H2O(g)39.2 3.92 -0.0376 5.66 x10-30.274 Given the two reactions shown with their equilibrium constants,PCl3(g) + ? O2(g) POCl3(g)K1NO(g) + ? O2(g) NO2(g)K2What is the equilibrium constant for the reaction, PCl3(g) + NO2(g) POCl3(g) + NO(g)K1K2K2/K1K1/K2(K1K2)-1K2K1The equilibrium constant for the reaction, H2(g) + I2(g)2 HI(g) is 54.9 at 699.0 K. What is the equilibrium constant for 4 HI(g) 2 H2(g) + 2 I2(g) under the same conditions? 109.80.00911 0.000332 109.8 0.0182 Using this data, 2 NO(g) + Cl2(g) 2 NOCl(g) Kc = 3.20 x 10-32 NO2(g) 2 NO(g) + O2(g) Kc = 15.5calculate a value for Kc for the reaction, NOCl(g) + ? O2(g) NO2(g) + ? Cl2(g)2.06 x 10-44.84 x 10-3 0.223 4.4920.2The reaction 2A(g) ? B(g) has a K value of 8. What is the value of K for the reaction ?B(g) ? A(g)20.1250.354.2564Part C: Solubility EquilibriumGiven the reaction at equilibrium:Zn(OH) ? Zn2+ + 2OHWhat is the expression for the solubility product constant, Ksp, for this reaction?Ksp = [Zn2+ ][OH-] / [Zn(OH)2]Ksp = [Zn(OH)2] / [Zn2+ ][2OH-]Ksp = [Zn2+ ][2OH-]Ksp = [Zn2+ ][OH-]2 Which of the following is the expression for the solubility product of Ca3(PO4)2?Ksp= [Ca2+]3 [PO43]2Ksp= [3 x Ca2+]3 [2 x PO43]2Ksp=3[Ca2+] x 2[PO43]Ksp=3[Ca2+]3 + 2[PO43]2Ksp= [Ca2+]3 [PO43]2The solubility of lead (II) chloride (PbCl2) is 1.6 x 10-2 M at 25oC. At this temperature, what is the Ksp of PbCl2?5.0 x 10-44.1 x 10-63.1 x 10-71.6 x 10-51.6 x 10-2 The solubility of manganese (II) hydroxide (Mn(OH)2) is 2.2 x 10-5 M. What is the Ksp of Mn(OH)2? 1.1 x 10-14 4.3 x10-14 2.1 x10-14 4.8 x10-10 2.2 x 10-5 What is the solubility product for AuCl3 if the molar solubility in a saturated solution is 3.3 x 10-7 M? 3.3 x 10-271.2 x 10-263.2 x 10-253.3 x 10-13 1.3 x 10-6The solubility of silver sulfate (Ag2SO4), in moles per liter, can be expressed in terms of the resulting ion concentrations. Which relationship is correct? solubility = 2[Ag+] solubility = [Ag+] solubility = [2Ag+] solubility = 2[SO42] solubility = [SO42] Which expression best describes the relationship between solubility product, Ksp, and the solubility, s, of MgF2?Ksp = 2x Ksp = x2 Ksp = 2x3Ksp = 4x2Ksp = 4x3What is the solubility, in mol/L, of PbI2, at a temperature where the Ksp = 8.5 x 10-9?4.6 x 10-59.2 x 10-51.3 x 10-32.0 x 10-3Calculate the concentration of iodide ion in a saturated solution of lead (II) iodide, PbI2 (Ksp is 1.4 x 10-8 ).4.2 x 10-43.1 x 10-31.5 x 10-33.5 x 10-9 1.4 x 10-8What is the solubility, in mol/L, of AgBr if the Ksp = 5.0 x 10-13?2.5 x 10-251.0 x 10-127.1 x 10-77.1 x 10-6Calculate the solubility in grams per liter (note that Ksp is in terms of moles and liters) of SrSO4 Ksp = 3.20 x 10?75.67 x 10-4 g/L3.2 x 10-7 g/L0.104 g/L0.208 g/LNone of the aboveWhich of the following compounds is the least soluble? Compound Ksp_______ MnCO3 1.8 x 10-11 CuS 6.3 x 10-36 CdS 8.0 x 10-27 PbS 8.0 x 10-28 MnCO3 CuS CdSPbSboth CdS and PbSGiven the following table of Ksp values, determine which compound listed has the greatest solubility. Compound Ksp_______ CdCO3 5.2 x 10- 12 Cd(OH)2 2.5 x 10-14 AgI 8.3 x 10-17 Fe(OH)3 4.0 x 10-38 ZnCO3 1.4 x 10-11 CdCO3 Cd(OH)2 AgI Fe(OH)3 ZnCO3 Calculate the maximum concentration (in M) of chloride ions (Cl-) in a solution that contains 0.100 M of Pb2+ if at 323 K the Ksp of PbCl2 is 1.0 x10-4.1.0 x10-4 1.0 x10-3 0.029 0.032 0.058 What is the solubility (M) of PbCl2 in a 0.15 M solution of HCl? The Ksp of PbCl2 at 25oC is 1.6 x10-5.2.0 x10-3 1.1 x10-4 1.8 x10-4 7.1 x10-4 1.6 x10-5 If 0.1 M aqueous solutions of the following pairs of substances are combined, which pair will yield a precipitate?sodium sulfide & ammonium chloridesodium sulfide & iron (III) chloridesodium hydroxide & potassium nitratenickel (II) nitrate & magnesium chloratepotassium chloride & aluminum nitrate Will a silver iodate precipitate form when 100 mL of 0.010 M AgNO3 is mixed with 10.0 mL of 0.015 M NaIO3? (Ksp of AgIO3 is 3.1 x 10-8)No, because Q < KYes, because Q < K No, because Q > KYes, because Q > K Not enough informationWill a silver sulfate precipitate form when 100 mL of 0.050 M AgNO3 is mixed with 10.0 mL of 0.0050 M Na2SO4? (Ksp of Ag2SO4 is 1.5 x 10-5)No, because Q < KYes, because Q < K No, because Q > KYes, because Q > K Not enough informationA solution contains 2.0 x 10-4 M Ag+ and 1.5 x 10-3 M Pb2+ . If sodium iodide, NaI is added, what [I-] will cause the first precipitate? (Ksp= 8.3 x 10-17 for AgI; Ksp= 7.9 x 10-9 for PbI2) 2.0 x 10-4 M I- will cause AgI to precipitate first4.2 x 10-13 M I- will cause AgI to precipitate first 5.3 x 10-6 M I- will cause PbI2 to precipitate first2.3 x 10-3 M I- will cause PbI2 to precipitate firstNot enough informationA solution contains 0.010 M Ba2+ and 0.010 M Sr2+. If sodium sulfate, Na2SO4 is slowly added, what [SO42-] will cause the first precipitate? (Ksp= 1.1 x 10-10 for BaSO4; Ksp= 3.2 x 10-7 for SrSO4) 1.1 x 10-8 M SO42- will cause BaSO4 to precipitate first1.1 x 10-10 M SO42- will cause BaSO4 to precipitate first 3.2 x 10-5 M SO42- will cause SrSO4 to precipitate first3.2 x 10-7 M SO42- will cause SrSO4 to precipitate firstNot enough informationWhich of the following compounds will be more soluble if the pH of a saturated solution is lowered? AgCl AgI PbCl2 NaCl Cr(OH)3In which of the following aqueous solutions would you expect AgCl to ave the lowest solubility? pure water 0.020 M BaCl2 0.015 NaCl 0.020 AgNO30.020 KCl In which of the following aqueous solutions would you expect AgCl to have the highest solubility? pure water0.020 M BaCl2 0.015 M NaCl0.020 M AgNO30.020 M KClAnswer KeyBBABBDDDBABDBECEEECCCDADDCCABBDBEEBDCABEAADCADBCCCDCBCBCCDCDADBCEECBCCBBDDBDABAEBAPart A and B Conceptual problemsIn which of the following systems would the number of moles of the substances present at equilibrium NOT be shifted by a change in the volume of the system at constant temperature?CO(g) + NO(g) CO2(g) + 1/2 N2(g)B) N2(g) + 3 H2(g) 2 NH3(g)N2(g) + 2 O2(g) 2 NO2(g)N2O4(g) 2 NO2(g)NO(g) + O3(g) NO2(g) + O2(g) Which of the following is the correct equilibrium expression for the hydrolysis of CO32? ?K = [HCO3? ] / ( [CO32? ] [H3O+] )K = ( [HCO3?] [OH?] ) / [CO32?]K = ( [CO32? ] [OH?] ) / [HCO3?]K = [CO32? ] / ( [CO2] [OH?]2 )K = ( [CO32? ] [H3O+] ) / [HCO3?] CuO(s) + H2(g) Cu(s) + H2O(g); ΔH = - 2.0 kilojoulesWhen the substances in the equation above are at equilibrium at pressure P and temperature T, the equilibrium can be shifted to favor the products byincreasing the pressure by means of a moving piston at constant Tincreasing the pressure by adding an inert gas such as nitrogendecreasing the temperatureallowing some gases to escape at constant P and Tadding a catalyst Oxalic acid, H2C2O4, is a diprotic acid with K1 = 5.36 x 10?2 and K2 = 5.3 x 10?5. For reaction below, what is the equilibrium constant?H2C2O4 + 2 H2O 2 H3O+ + C2O42?5.36 x 10?25.3 x 10?52.8 x 10?61.9 x 10?101.9 x 10?13 4 HCl(g) + O2(g) 2 Cl2(g) + 2 H2O(g)Equal numbers of moles of HCl and O2 in a closed system are allowed to reach equilibrium as represented by the equation above. Which of the following must be true at equilibrium?I. [HCl] must be less than [Cl2].II. [O2] must be greater than [HCl].III. [Cl2] must equal [H2O].I onlyII onlyI and III onlyII and III onlyI, II, and III SO3 (g) 2 SO2 (g) + O2 (g) After the equilibrium represented above is established, some pure O2 (g) is injected into the reaction vessel at constant temperature. After equilibrium is reestablished, which of the following has a lower value compared to its value at the original equilibrium? Keq for the reactionThe total pressure in the reaction vessel.The amount of SO3 (g) in the reaction vessel.The amount of O2 (g) in the reaction vessel.The amount of SO2 (g) in the reaction vessel. The reaction represented below has an equilibrium constant equal to 3.7 x 104. Which of the following can be concluded from this information? HC2H3O2(aq) + CN?(aq) HCN(aq) + C2H3O2?(aq) Acid base conj.acid conj.baseCN?(aq) is a stronger base than C2H3O2?(aq) HCN(aq) is a stronger acid than C2H3O2?(aq) The conjugate base of CN?(aq) is C2H3O2?(aq)The equilibrium constant will increase with an increase in temperature.The pH of a solution containing equimolar amounts of CN?(aq) and C2H3O2?(aq)) is 7.0. 231140049847500The energy diagram for the reaction X + Y Z is shown above. The addition of a catalyst to this reaction would cause a change in which of the indicated energy differences?I onlyII onlyIII onlyI and II onlyI, II, and III For the equilibrium system: CO(g) + 2 H2(g) CH3OH(l) , what is Kc ?Kc= CH3OH/2(CO) (H2)Kc= CH3OH/(CO) (H2)2Kc= 1/ 2(CO)(H2)Kc=1/ (CO)(H2)2Consider the system at equilibrium: 2SO2(g) + O2(g) 2SO3(g) for which ?H < 0. Which change(s) will increase the yield of SO3(g)? Increasing the temperature Increasing the volume of the containerI only II only Both I and II Neither I nor II H2 (g) + I2(g) 2HI(g) ΔH>0Which of the following changes to the equilibrium system represented above will increase the quantity of HI(g) in the equilibrium mixture/adding H2(g)increasing the temperaturedecreasing the pressureI onlyIII onlyI and II onlyII and III onlyI, II and IIIHCO3-(aq) + OH-(aq) H2O(l) + CO32- (aq) ΔH = -41.4kJWhen the reaction above is at equilibrium at 1atm and at 250C, the ratio [CO32-]/[HCO3-] can be increased by doing which of the following?Decreasing the temperatureB)Adding acidC)Adding catalystD)Diluting the solution with distilled waterE)Bubbling neon gas through the solutionWhich statement is correct about a system at equilibrium? The forward and reverse reactions occur at identical rates.The concentrations of reactants must equal the concentrations of the products.The concentrations of reactants and products can be changed by adding a catalyst.The concentrations of reactants and products are not affected by a change in temperatureFor which reaction at equilibrium will an decrease in volume at constant temperature cause a decrease in the amount of product? (A) N2 (g) + 3H2 (g) 2NH3(g)(B) HCl(g) + H2O(l) H3O+(aq) + Cl–(aq)Fe3O4 (s) + 4H2(g) 3Fe(s) + 4H2O(g)CaCO3(s) CaO(s) + CO2(g)P4(s) + 5 O2(g) P4O10(s) The equilibrium constant isKc = [P4O10] / [P4] [O2]5Kc = [P4O10] / 5 [P4] [O2]Kc = [O2]5Kc = 1 / [O2]5 Fe3O4(s) + 4 H2(g) 3 Fe(s) + 4 H2O(g) ΔH > 0 For this reaction at equilibrium, which changes will increase the quantity of Fe(s)? 1. increasing temperature2. decreasing temperature3. adding Fe3O4(s) 1 only1 and 2 only2 and 3 only1,2, and 3 What is the relationship between the equilibrium constant (Kc) of a reaction and the rate constants for the forward (kf) and backward (kb) steps? Kc = kf kb Kc = kb / kf Kc = kf / kb Kc = 1 / (kfkb) Which factors will affect both the position of equilibrium and the value of the equilibrium constant for this reaction? The H = - 92 kJ, N2(g) + 3 H2(g) \s2 NH3(g)increasing the volume of the containeradding N2removing NH3lowering the temperature For which reaction at equilibrium does a decrease in volume of the container cause a decrease in product(s) at constant temperature?CaCO3 (s) CaO(s) + CO2(g)B) 2SO2 (g) + O2 (g) 2SO3(g) C) HCl(g) + H2O(l) H3O+(aq) + Cl–(aq)D) SO2(g) + NO2(g) SO3(g) + NO(g)N2O4(g) 2NO2(g)The equilibrium reaction shown is endothermic as written. Which change will increase he mount of NO2 at equilibrium?adding a catalystdecreasing the temperatureincreasing the volume of the containeradding an inert gas to increase the pressure2SO2(g) + O2(g) 2SO3(g) ?H < 0Which change(s) will increase the quantity of SO3 (g) at equilibrium?increasing the temperaturereducing the volume of the containeradding He to increase the pressureI only II onlyI and III only II and III onlyPart C Conceptual ProblemsThe best explanation for the solubility of MnS in dil HCl is thatThe solubility product of MnCl2 is less than that of MnSConcentration of Mn2+ is lowered by the formation of comples ions with chloride ionsConcentration of sulphide ions is lowered by oxidation of free sulphurConcentration of sulphide ions is lowered by the formation of the weak H2SBecause of the formation of more MnCl2The solubility of AgI in NaI solution is less than that in pure water becauseAgI forms comples with NaIof common ion effect solubility product of AgI is less than that of NaIthe temperature of the solution decreasesnone of the abovethe solubility product of CuS, Ag2S and HgS are 10-31, 10-44 and 10-54 respectively. The solubility of these sulphides are in the orderAg2S> CuS >HgSAg2S > HgS > CuSHgS> Ag2S > CuSCuS > Ag2S > HgSHgS > CuS > Ag2SWhat is the correct expression for the solubility product of SnS2 ?[Sn2+] [S2-]2[Sn4+] [S2-]2 [Sn2+] [2S2-]2 [Sn4+] [2S2-]2 [Sn2+]2 [S2-]2 The solubility of CaCO3 in water is 3.05 x10-4 moles/L. Its solubility product will be6.1 x10-49.33.05 x10-49.3 x 10-815.4The solubility of A2X3 is y mol dm-3. Its solubility product is6y464y436y5108y56y5Consider the following solubility data for various chromates at 25oC.KspAg2CrO49.0 x 10-12BaCrO42.0 x 10-10PbCrO41.8 x 10-14 The chromate that is the?most?soluble in water at 25oC on a molar basis is:Ag2CrO4BaCrO4C) PbCrO4D) impossible to determineE) none of theseWhat is the molar solubility, s, of Ba3(PO4)2?in terms of Ksp?s = Ksp1/2B)) s = Ksp1/5s = [Ksp/27]1/5s = [Ksp/108]1/5s = [Ksp/4]5Ag3PO4?would be?least?soluble at 25oC in0.1 M AgNO30.1 M HNO3pure water0.1 M Na3PO4solubility in (a), (b), (c), or (d) is not differentWhen we mix together, from separate sources, the ions of a slightly soluble ionic salt, the salt will precipitate if Qsp?_____ Ksp, and will continue to precipitate until Qsp?_____ Ksp.is greater than; equalsis less than; is greater thanis less than; equalsequals; is less thanequals; is greater thanWhich of the following pairs of compounds gives a precipitate when aqueous solutions of them are mixed? Assume that the concentrations of all compounds are 1.0 M immediately after mixing.CuBr2?and K2CO3HNO3?and NH4IBaCl2?and KClO4Na2CO3?and H2SO4KCl and KNO3Which of the following occurs when excess of concentrated NH3 (aq) is mixed with 0.1M Cu(NO3)2(aq) ?A dark red precipitate forms and settles outSeparate layers of immiscible liquids form with a blue layer on top.The color of the solution turns from light blue to dark blue.Bubbles of ammonia gas form.The pH of the solution decreases.A yellow precipitate forms when 0.2 M NaI is added to a 0.2M solution of which of the following ions?Zn2+Pb2+CrO4 2-SO42-OH-Which solution below could selectively precipitate lead alone from the mixture if it has Fe2+, Cu2+ and Pb2+ ions? sodium sulfide soium hydroxidedil. Hydrochloric aciddil Nitric aciddil AmmoniaWhen 50 ml each of 0.1 M Li3(PO4) and Ag(NO3) are mixed together, yellow precipitate of silver phosphate is produced. Which of the following ions is the major component in the solution?[PO43- ][NO3-][Ag+][Li3+]They are all equalIf 100ml each of 0.1M of Ba(OH)2 and Na2 (SO4) are mixed together, what would be the concentration of the hydroxide ions in solution?0.2 M0.1M1.0M.02M0.01M Referring to the above question, what would be the concentration of [SO42-] ions in the resulting solution?0.1M0.5M1.0Mnegligible amount0.05MWhen aqueous NH3 is first added to a solution containing Ni2+, a precipitate forms, but when an excess of aqueous NH3 is added, the precipitate dissolves. Which of the below explains why the precipitate dissolves?Ni2+ forms hydrogen bonds with NH3Ni2+ forms hydrogen bonds with NH3Ni2+ forms complex ion with NH3Ni2+ is oxidized to Ni3+Ni2+ is reduced to Ni1+ Which of the following ions are generally insoluble in cold water?AcetatePotassiumPhosphateNitrateAmmoniumA student mixes equal volumes of 1.0M solutions of Tin chloride and 1.0 M copper sulfate and observes that no precipitate forms. Then the student mixes equal volumes of 1.0 M solutions of sodium sufide and copper sulfide and observes the formation of a precipitate. The formula of the precipitate must beCuSCuCl2CuClNa2(SO4)2 NaSO4Conceptual Problems Answer KeyEBBCCBADDACAAADACDACBDBABDAADAAACBCDCDCCA ................
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